Chemical bonding and electronic structure of B2O3, H3BO3, and BN: An ESCA, Auger, SIMS, and SXS study

Abstract

We have measured the ESCA, Auger, and SIMS spectra of B₂O₃ (boron trioxide) and the Auger and SIMS spectra of H₃BO₃ or B(OH)₃ (boric acid). The ESCA data of B₂O₃ are used with published soft‐x‐ray‐emission (SXS) data to determine the electronic structure of boron trioxide and to make deductions about chemical bonding. This was similarly done for boron nitride using published ESCA and SXS results of other workers. Both of these compounds were found to be partly covalent and partly ionic, and bonding was described in terms of σ bonds in B₂O₃, and σ and π bonds in BN. Thus, the electronic structure of boron nitride is similar to graphite. A detailed picture of the electronic structure of B₂O₃ enabled us to understand its KLL Auger spectrum. Two broad peaks were interpreted as KLL band‐structure features while fine structure was found to be due to extrinsic plasmons. A similar interpretation was presented for H₃BO₃. The SIMS spectra of B₂O₃ and H₃BO₃ reflected similar structural units in the two compounds; covalent bonding; and weaker B–O bonds in H₃BO₃.